As if catching plankton and sneaking a peak with the microscope wasn’t exciting enough (see the picture of the larval eel!), there’s a lot more data being collected on this ship. All of it helps scientists understand what’s going on in this part of the Ocean. And some of it I am able to help with, which is my favorite thing about this cruise (well, maybe that and the incredible views).

I was able to examine some of the plankton samples with a microscope. Do you see the larval eel in the tray next to the scope?

The CTD rosette and niskin bottles

At some of our stations, we lower a big and important science tool (called a rosette) into the ocean that contains niskin bottles (bottles used for water sampling) and a Conductivity, Temperature, and Depth meter (CTD). As the rosette is lowered into the depths and raised back up, the scientists can remotely operate the open niskin bottles to snap shut at specific depths. This allows each bottle to come up to the surface with a sample of water from many different depths! Meanwhile, the CTD can take measurements of conductivity (which indicates the salinity of the water), temperature, and pressure, among other things. Scientists have thought of many ways to collect A LOT of data at one time.

Bringing the CTD up from the depths.

When the CTD comes back onto the ship, it’s time for us to use the samples for different purposes. We collect water from 3 different bottles (so 3 different depths) to test the amount of chlorophyll in the water. Do you know what the chlorophyll comes from? If you said plants, you’re right! What are some plant-like things that are drifting all over the ocean? You guessed it! Phytoplankton! So the amount of chlorophyll gives scientists evidence as to how much phytoplankton is in the water. But first, we need to extract (take out) the chlorophyll from the water. We run the water through special filters and soak the filters in a chemical that extracts the chlorophyll. Then we can put the sample through a special machine that uses light to sense the amount of chlorophyll. Wow. One thing I am learning on this trip is how important light is in understanding a water ecosystem.

Me extracting chlorophyll samples

Do you remember what a hypothesis is? It’s an educated guess that answers a scientific question. When scientists come up with a hypothesis, it gives them something to test in an investigation. If you were presented with the question, “At what depth is phytoplankton most abundant?”, what would be your hypothesis?

Another thing we do with the water samples is collect a bit from most of the bottles to preserve and send to the lab to test for the amount of nutrients. When you think of nutrients, you probably think of healthy vitamins for people. But nutrients for plants are actually made from broken down waste of animals. It’s important for ocean water to have a balanced amount of nutrients so that phytoplankton can be healthy. But too much nutrients can also cause algae and phytoplankton to overpopulate!

But that’s not all! The scientists also take samples from the niskin bottles to test for Dissolved Inorganic Carbon (DIC). That sounds fancy, I know. Doing this basically helps scientists understand the pH of the water and look for evidence of ocean acidification (a result of climate change).

Jessica and I taking nutrient samples from the niskin bottles

Can you believe how much scientists can learn from dropping a big science tool into the water?

Scientist Spotlight – Harvey Walsh

Harvey is our Chief Scientist on the mission, meaning he oversees all of the scientific work happening on the ship. He has been so kind as to answer all of my many questions, including these:

Me – If you could invent any tool to make your work more efficient, what would it be and why?

Harvey – I would like a tool that allows you to easily and quickly identify fish eggs and larvae. Currently, it is a time consuming process that involves sorting through samples and identifying them in the lab. There have been and continue to be efforts to use image analysis and genetics to speed up the process. An image analysis has progressed quicker for phyto- and zooplankton, but fish and fish eggs still lag behind.

Me – When did you know you wanted to pursue a career in ocean science?

Harvey – I always thought I would end up studying freshwater fisheries in Minnesota, where I grew up, but after the first two ocean cruises I participated in, I knew the ocean was more for me and the lakes had less of an appeal.

Me – How long has EcoMon (the ecosystem monitoring program we are using) been conducted and how was the protocol (the methods we use) created?

Harvey – EcoMon started in 1992 but it was modeled after a program that started in 1977. The bongo plankton sampling has not changed much since it started, but with new technology we have added the water chemistry

Harvey relaxing in the bridge deck

testing, optics, and other instruments.

To create the protocol, scientists from around the North Atlantic region got together to form the International Commission for the Northwest Atlantic Fisheries. This council had the job of looking at plankton sampling techniques and deciding the best way to monitor plankton communities.

Me – Can you share an example of a way that people have used EcoMon data to form and test a hypothesis?

Harvey – Our data helps scientists make connections between different species in a food web, for example. After people noticed that Atlantic herring (fish) populations were getting low, they used EcoMon data to come up with a hypothesis like this:

“Increasing haddock populations lead to a lower stable state of herring because haddock feed on herring eggs.”

If people want to know more about a certain species of fish and how it survives and thrives, they need to understand the whole ecosystem, including the food web!

Personal Log

This cruise continues to amaze me. Sometimes we’ll have several hours between stations when I love to learn from others, bring a pair of binoculars up to the fly bridge and join the seabird observers, or catch up on a good book. Being around the water all day is calming and serene. I feel that this is the opportunity of a lifetime.

Another rare opportunity came yesterday when I was able to launch my drifter buoy as part of the NOAA drifter buoy program! First, I decorated the buoy with our school’s name and a symbol for each of the classes at our school – the Sharks class, the Rays class, the Dolphin class, and the Sea Star class. Then, after gaining permission from the ship command, we dropped the buoy overboard!

The buoy has a long canvas tube that extends out like a spring after you release it. This allows the buoy to have a long tail that reaches into the water so that it can catch the ocean currents and drift. If it was just the floating buoy, it would get moved by the wind instead of the currents.

Everyone runs to the bow when dolphins are riding the wake!

The buoy has a satellite tag that sends a signal to a satellite wherever it goes. This way, back home my students and I can track the buoy online and see where it ends up! Where do you think the buoy will go?

Everyone on board gets excited when we spot a pod of dolphins or a whale spout! I can’t wait to see what’s out there tomorrow!

Did You Know?

Great Shearwaters are sea birds that spend most of their lives out at sea and only come to land to nest. They can dive deep to catch fish but do not have to dry out their wings like some other birds. They are almost always found soaring by air currents and they prefer stormy and rough weather for stronger air patterns to lift them up.

A great shearwater in flight. Photo courtesy of NOAA.

Challenge Yourself

If a plankton sample with 5,000 individual plankton contains 60% salps, 10% hake larvae, 20% arrow worms, and 10% crab megalops, how many arrow worms are in the sample?

Here’s a picture of an arrow worm from under a microscope. They are about the size of the letter “I” on your keyboard. Photo courtesy of NOAA.